Enhanced transport phenomena and performance in proton exchange fuel cells using triangular flow field obstacles with...

Area of Science:

• Energy Conversion
• Electrochemical Engineering
• Computational Fluid Dynamics

Background:

• Proton exchange membrane fuel cells (PEMFCs) are crucial for clean energy, but their efficiency is limited by transport phenomena.
• Optimizing reactant distribution and water management is key to enhancing PEMFC performance and durability.

Purpose of the Study:

• To numerically investigate the impact of triangular obstacles on PEMFC transport phenomena and electrochemical performance.
• To analyze how different obstacle aspect ratios affect oxygen velocity, reactant consumption, temperature, and water content.
• To determine the optimal obstacle design for improved power density and stable operation.

Main Methods:

• Numerical simulations were performed to analyze fluid flow, species transport, and thermal characteristics within a PEMFC.
• Polarization curves and power density were calculated to evaluate electrochemical performance.
• Membrane water content and cathode flooding were assessed to understand water management.
• Sensitivity analyses were conducted on operating parameters like temperature, pressure, and humidity.

Main Results:

• Triangular obstacles enhanced local convective mixing, increasing maximum oxygen velocity by over 35%.
• The aspect ratio 1 (AR=1) triangular obstacles resulted in up to a 24% increase in maximum power density.
• Obstacles improved water management, preventing membrane dehydration and cathode flooding under diverse operating conditions.
• Performance enhancements were observed across various temperatures, pressures (up to 2 atm), and relative humidity levels.

Conclusions:

• Optimized triangular obstacles are effective in improving oxygen accessibility and reactant distribution in PEMFCs.
• These structures significantly enhance electrochemical performance and ensure stable operation by optimizing water balance.
• Triangular obstacles represent a promising design strategy for advancing next-generation PEMFC technology.